#5226: <<loop>> with -threaded -feager-blackholing, but only sometimes
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Reporter: dreixel | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
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While benchmarking the performance of GHC's SMP parallelism, I ran into an
issue where (rarely) a test would fail with `<<loop>>`. I tried hard to
reduce this to a single file, which I am attaching to this report.
To reproduce, compile the program with `--make -threaded -feager-
blackholing -rtsopts -O1` and run multiple times with `-Nm` with `m>=2`.
In my case, using `N8` (on a machine with 8 cores), I once got the error
after 35 tries, but sometimes it takes thousands of attempts. I'm also
attaching a bash script to compile and run the test repeatedly.
Tested with current HEAD, built on a Intel Xeon E5320, "perf" settings
without dynamic linking. But I think I also encountered this behavior in
GHC 7.0.3.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5226>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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